400 Vnivi rsity of California Publications in Zoology. [Vol. 6 



the opening of the penis. The right testis is composed of two 

 lobes, the right and larger of which extends from the posterior 

 level of the left testis forward to the anterior extremity of the 

 body. The left lobe, attached by a narrow bridge posterior to 

 the base of the acetabulum, lies to the left of the acetabulum 

 and in front of the vaginal opening. The testes lie within the 

 longitudinal muscle mass, in a position identical with that occu- 

 pied by the ovaries in the posterior portion of the bodj r . They 

 are considerably larger than the ovaries, as is shown in plate 39, 

 figure 42, and are composed of loosely-aggregated follicles. Each 

 follicle is covered with a fibrous nucleated layer, the "tunica 

 propria" of Lonnberg, continuous with the walls of the tubules 

 into which the follicle opens. These unite into two main vasa 

 efferentia and empty into a large median vesicula seminalis 

 situated immediately in front of the uterus, nearest the ventral 

 surface. This structure is perhaps more accurately described 

 as a vas deferens, more or less uniformly dilated by the masses 

 of spermatozoa. It coils from left to right and from dorsal to 

 ventral, in three large convolutions (pi. 41, fig. 46), dilating 

 near its anterior extremity to form a bulb, and opening through 

 a muscular papilla into a thick-walled tube, the cirrus-pouch or 

 ejaculatory duet. The wall of this pouch is thick and well sup- 

 plied with muscles. Its inner lining is greatly folded and covered 

 with delicate spinules. This duct passes almost straight dorsad, 

 turning a little to the left, opening on a rounded papilla on the 

 dorsal surface, a little to the left of the median line and anterior 

 to the mouth of the vagina on the ventral surface. The wall of 

 the duct grows much thinner toward its distal end and its lumen 

 increases somewhat. Heavy bundles of muscle fibres running at 

 right angles to the course of the ejaculatory duct are attached 

 to its wall throughout the whole of its course (rad. muse. /'., pi. 

 43, fig. 65). Outside these lies a large mass of gland-cells extend- 

 ing the whole length of the ejaculatory duct. They are very large 

 granular cells, with definite cell-walls forming intracellular 

 canals (prost. <jl.. pi. 43, fig. 64). These empty into numerous 

 delicate ducts opening on the surface of the ejaculatory duct 

 and probably constitute a prostate gland. Outside this gland lie 

 heavy longitudinal muscle bundles, a part of the body muscula- 



